Various methods exist for imaging the shape of an internal and external human organ.
The first consists in using an impression paste of greater or lesser elasticity and in reconstructing the part by plaster casting in order to obtain the complete reproduction of said organ.
A second method described by Moshabac in 1977 (U.S. Pat. No. 4,182,312) and then by Becker (U.S. Pat. No. 4,411,626) consists in micro-tracing the surface being studied and, where appropriate, reconstructing it using a micro-profiler.
A third method consists in taking an X-ray or tomodensitometric reading, then in repositioning each section as a function of the position of the X-ray analysis receivers and sensors.
A fourth method consists in using the NMR principle (nuclear magnetic resonance) or MRI principle (MR imaging), known methods which have been widely described and permit reconstruction of the part using a numerically controlled micro-profiler (Information dentaire, September 1988).
Finally, a new method described in a series of previous documents uses stereoscopic methods (Rooder) or moire effect methods (Duret) and makes it possible to take a three-dimensional reading of the objects photographed.
This last method, introduced very recently in dentistry, makes it possible to form an image, but does not afford the possibility of correlating various images in order to obtain an overall view of the part which is the subject of the study.
In particular, the only means used in order to correlate views presupposes the fixing of the object analyzed and of the camera in known positions of the computing and analysis center. Thus, it is relatively common nowadays to effect a rotation of the object facing the analysis camera. Such a technique is difficult to implement in the case of the imaging of a part of the jaw of a subject, in the case of dentistry.